Disseminated sulphide mineralisation at Garbh Achadh, Argyllshire, Scotland

A brief investigation of low-grade copper mineralisation associated with a small, talc-alkaline porphyry intrusion of Caledonian age is described. Geological mapping has delineated a small stock of biotite-feldspar 2 porphyry, 0.25 km in area, intruded into a sequence of Dalradian schists and quartzites with inter-bedded epidiorites. Disseminated sulphides occur within the porphyry and the hornfelsed epidiorite but do not normally , exceed 3% of the rock by volume. Assays of both rock types obtained maximum levels of 0.24% Cu. Hydrothermal alteration is prominent within the porphyry, with the widespread development of sericite and kaolinite. Subsequent faulting apparently exerted some control on the present limits of alteration and mineralisation. Several small strata-bound lenses of massive sulphide within the metasediments were recorded but were not investigated in detail. Geochemical rock-sampling delineated a strong arcuate copper anomaly over the northern epidiorite/porphyry contact and a more subdued anomaly along the southern faulted contact. Molybdenum shows a similar distribution but is more closely confined to the porphyry. Overburden sampling demonstrated that little or no metal dispersion occurred within the overlying till, and stream sediment sampling of the catchment area showed that concentrations of copper decrease to background levels within 1 km of the intrusion. 1 Induced polarisation (IP) surveys produced a clearly defined grouping of chargeability anomalies around the edges of the porphyry stock but these showed no increase in magnitude at depth. Above background chargeability values recorded over the centre of the intrusion increase markedly towards the margins , possibly reflecting a pyritic halo. Most resistivity 'lows' coincide with fault zones and the results of a total intensity magnetometer 1 survey showed that, while most magnetic anomalies occur over epidiorites, I significant anomalies are also produced in the vicinity of fault zones. The results of the geological, petrographic, geochemical and I geophysical studies demonstrate the presence of several features : characteristic of 'porphyry copper style' mineralisation but the small 1 surface area and low grade of the deposit, combined with a lack of encouraging geophysical responses at depth, suggest that there is little II chance of discovering an economic orebody by exploratory drilling

Mineral reconnaissance at the Highland boundary with special reference to the Loch Lomond and Aberfoyle areas

Serpentinite bodies at the Highland Boundary in the Loch Lomond and Aberfoyle areas are extensively altered to magnesite-quartz and ferroan-dolomite-quartz rocks. Silicification was probably initiated before conversion to carbonate. Relict textures indicate that the serpentinites were derived from peridotitic precursors, but one unaltered ultrabasic sample comprises mainly chromian diopside. Chromite geochemistry and hornblende-schist mineralogy rein force the ophiolitic character of the serpentinite-spilite-blackshale- chcrt assemblage of the Highland Border. Magnetic and VLF traverses across the Highland Boundary fracture-zone near Helensburgh identified several anomalous zones. One may be due to a concealed serpentinitic sheet. The most mineralised serpentinite body showed chromium values in the range 1000 to 3035 ppm. Such concentrations arc not encouraging for the small serpentinites at Loch Lomond and Aberfoyle, but may be significant regarding larger serpentinites elsewhere at the Highland Border

The Ordovician trilobite Hadrohybus Raymond 1925, and its family relationships

The type species of the trilobite Hadrohybus Raymond 1925, H. dunbari from the Cow Head Group of western Newfoundland, is redescribed here. It has been regarded as a cheirurid, but analysis of its cranidial characters show that it is a bathyurid closely related to the well-known Early Ordovician genus Bolbocephalus, and it is considered to be a subgenus of that form. It is probably of early Middle Ordovician age. A second Hadrohybus species occurs in the late Early Ordovician of Vermont

Lead, zinc and copper mineralisation in basal Carboniferous sediments at Westwater, south Scotland

A zioneo f lead, zinc and copperm ineralisatioins developedo ver a minimum I of 4 km of strikeo f basal Carboniferoucse mentstoneg roup sedimentsa nd immediatelyu nderlyingB irrenswarkL avas atwestwater,n ear Laqholm in south Scotland. Grades so far obtained from sparse rock exposures and from shallow boreholes a fissure sulphides are usuallyO .l-O.j%o f combinedm etals over 1-2 m of thickness,bu t vein of higher grade and a relativelyt hick zone of disseminated were also located. Galena, sphalerite,c halcopyritea ndbaryte occur mainly in thin dolomitev eins but disseminationosf galenaa re also presenti n sandstoneu nits. The mineralisatioins of low temperaturet ype I was emplaceda long northeasterlyt rendingn ormal faultsa nd cross faults regardeda s late Carboniferouisn age. and Mineralisatiohna s been controlledb y faulting,r egionalf aciesv aziation and local lithologicalv ariationa s well as by stratigraphipco sition. These controlsa re applicablei n furthere xplorationo f Lower Carboniferourso cks in both south and central Scotland. The heavy mineral fraction of stream sediment is the optimums amplingt ype in reconnaissanceex plorationo f areas of calcareous . rocks such as the Lower Carboniferouso f south Scotlanda nd basal till sampling is the most effectivem ethod of follow-upe xplorationi n those areas where glaciald epositsa re widespreada nd often thick

Investigation of stratiform sulphide mineralisation at Meall Mor, South Knapdale, Argyll

A co-ordinated geochemical-geophysical-geological investigation of copper mineralisation in the Meal1 ?46r area, South Knapdale, Argyll was carried 0th in 1976 and followed by a drilling programme of 3 shallow holes in early 1977. The mineralisation occursin a zone of weak stratiform sulphide mineralisation (the pyrite zone) with a strike length of 1Okm in the Upper &ins Quartz&e of the Middle Dalradian. The geochemical drainage survey showed the existence of a strongly anomalous distribution of Cu and Sb in the Abhainn Srathain draining south from . Meal1 M&- and detailed soil sampling over the pyrite zone outlined a broad area enriched in copper. Deeper soil sampling confirmed the anomalously high copper values and a coincident IP anomaly was found stretching from Meal1 M& south to the old mine workings on Abhainn Srathain, and is probably caused by a local enrichment of pyrite and chalcopyrite within the pyrite zone. Three boreholes were drilled; two on coincident geochemical and geophysical anomalies, and the third beneath the old mines at Abhainn Srathain. Copper values in the first two holes range up to 0.24% Cu over 4.27m, but up to 1.06% Cu over 2.67m in the third and this enrichment may be related to a later remobilisation of the disseminated chalcopyrite. The results of subsequent drilling at two other sites are given in Appendix III

The only known cyclopygid–‘atheloptic’ trilobite fauna from North America: the upper Ordovician fauna of the Pyle Mountain Argillite and its palaeoenvironmental significance

The trilobite fauna of the upper Ordovician (middle Katian) Pyle Mountain Argillite comprises a mixture of abundant mesopelagic cyclopygids and other pelagic taxa and a benthic fauna dominated by trilobites lacking eyes. Such faunas were widespread in deep water environments around Gondwana and terranes derived from that continent throughout Ordovician time but this is the only known record of such a fauna from North America and thus from Laurentia. It probably reflects a major sea level rise (the ‘Linearis drowning events’) as does the development of coeval cyclopygid-dominated deep water trilobite faunas in terranes that were marginal to Laurentia and are now preserved in Ireland and Scotland. The Pyle Mountain Argillite trilobite fauna occurs with a deep water Foliomena brachiopod fauna and comprises 22 species. Pelagic trilobites (mostly cyclopygids) constitute 36% of the preserved sclerites, and 45% of the fauna is the remains of trilobites lacking eyes, including one new species, Dindymene whittingtoni sp. nov. Three species of cyclopygid are present, belonging in Cyclopyge, Symphysops and Microparia (Heterocyclopyge). Cyclopygids are widely thought to have been stratified in the water column in life and thus their taxonomic diversity reflects the relative depths of the sea-beds on which their remains accumulated. A tabulation of middle and upper Katian cyclopygid-bearing faunas from several palaeoplates and terranes arranged on the basis of increasing numbers of cyclopygid genera allows an assessment of the relative depth ranges of the associated benthic taxa. The Pyle Mountain Argillite fauna lies towards the deeper end of this depth spectrum

Generative techniques in composition

In this project, I used generative and algorithmic processes to produce raw material for further development, acting as both composer and curator, and eventually producing a series of compositions that combine random elements with human embellishment. Building on techniques and approaches pioneered by indeterministic composers such as John Cage and his contemporaries (as well as the later generative artists, beginning with Brian Eno), I applied the perspective of indeterminate music in the context of more mainstream or dance-oriented music. The first piece I produced was stylistically rooted in modern electronic music but consists of note events whose timings derived from mathematical games. Following this, using a polysynth made with Max/MSP, I pastiched the use of short, timbrally contrasting samples in electronic music, without using existing sound sources, resulting in a piece that uses randomly selected timbres and pitch content. The process and presentation of these pieces considered altogether positions the role of the creator as an entity beside the work, rather than preceding it, and posits that the role of the listener is inherently creative. The final submission of this project is a collection of audio pieces, a collection of Max/MSP patches, and this written commentary. The audio pieces are numbered according to their status, with the whole numbers 1 and 2 being the two main pieces, each unique in concept, and pieces with decimal numbers being compositions that explore related concepts to those, either as a tangent, an alternate take on the idea, or just a demonstration of the processes involved

The shape of life: how much is written in stone?

Summary Considering the enormous diversity of living organisms, representing mostly untapped resources for studying ecological, ontogenetic and phylogenetic patterns and processes, why should evolutionary biologists concern themselves with the remains of animals and plants that died out tens or even hundreds of millions of years ago? The reason is that important new insights into some of the most vexing evolutionary questions are being revealed at the interfaces of palaeontology, developmental biology and molecular biology. Attempts to synthesise information from these disciplines, however, often encounter their greatest hurdles in considerations of the radiation of the Metazoa. Ongoing challenges relate to the origins of body plans, the relationships of the metazoan phyla and the timing of major evolutionary radiations. Palaeontology not only has its own unique contributions to the study of evolutionary processes, but provides a lynchpin for many of the emerging techniques

The position of graptolites within Lower Palaeozoic planktic ecosystems.

An integrated approach has been used to assess the palaeoecology of graptolites both as a discrete group and also as a part of the biota present within Ordovician and Silurian planktic realms. Study of the functional morphology of graptolites and comparisons with recent ecological analogues demonstrates that graptolites most probably filled a variety of niches as primary consumers, with modes of life related to the colony morphotype. Graptolite coloniality was extremely ordered, lacking any close morphological analogues in Recent faunas. To obtain maximum functional efficiency, graptolites would have needed varying degrees of coordinated automobility. A change in lifestyle related to ontogenetic changes was prevalent within many graptolite groups. Differing lifestyle was reflected by differing reproductive strategies, with synrhabdosomes most likely being a method for rapid asexual reproduction. Direct evidence in the form of graptolithophage 'coprolitic' bodies, as well as indirect evidence in the form of probable defensive adaptations, indicate that graptolites comprised a food item for a variety of predators. Graptolites were also hosts to a variety of parasitic organisms and provided an important nutrient source for scavenging organisms